Heat exchanger



Sept. 8, 1970 A. w. LOSSING 3,527,290

HEAT EXCHANGER Filed Aug. 26, 1968 2 Sheets-Sheet 1 l um.

INVENTOR ALFRED W. LOSSING BY W A Arm/w? p 970 A. w. LOSSING 3,527,290

HEAT EXCHANGER Filed Aug. 26, 1968 2 Sheets-Sheet 2 United States Patent 3,527,290 HEAT EXCHANGER Alfred W. Lossing, Derby, N.Y., assignor to The Durion Company lino, Dayton, Ohio, a corporation of New York Filed Aug. 26, 1968, Ser. No. 755,360 Int. Cl. F28f 9/02; F161 /00 US. Cl. l65-70 8 Claims ABSTRACT OF THE DISCLOSURE The housing of a heat exchanger encloses multiple tubes each terminating at an end plate having a flat face, and a pivotally supported head member includes a mating flat face and multiple passages which align with the tubes. Resilient annular gaskets are located between the faces in surrounding relation with the ends of the passages, and each gasket includes a portion which projects into a corresponding annular recess formed within the face of the head member. 7

BACKGROUND OF THE INVENTION In a heat exchanger including an elongated cylindrical casing or housing adapted to receive a heat transfer fluid and enclosing a plurality of axially extending interconnected tubes each terminating at an end plate, commonly a pivotally supported head is secured to the end plate with peripherally spaced screws. The head incorporates a plurality of U-shaped return passages and inlet and outlet passages which align with the tubes within the housing to provide for directing the fluid to be heated or cooled in a serpentine-like flow path through the tubes.

Usually, the end plate and the head have mating flat circular faces, and a large flat resilient gasket is employed between the faces covering the entire area of each face. The gasket has a plurality of holes which align with the passages within the head and the tubes within the housing for preventing the fluid being circulated through the tubes and passages from flowing from one passage to another between the faces of the end plate and the head.

When such a heat exchanger is employed for cooling a liquid food product such as beer during its processing, it is not unusual for the housing and the head to be subjected to a wide temperature range. For example, in the production of beer, the heat exchanger may initially receive the beer at approximately 200 F. from a boiler or pasteurizer for purposes of cooling the beer down to a temperature of 50 F. Furthermore, the heat exchanger is frequently used to remove the heat generated by fermentation and for final cooling of the beer down to 36 F. at the conclusion of the fermenting cycle, and it is also common to employ the heat exchanger to cool the beer to approximately 28 F. immediately before filtering, bottling, or filling kegs.

As a result of the heat exchanger being subjected to the substantial temperature range of 28 F. to 200 F. and the closing forces imparted by the peripherally spaced screws, the head will warp or bow slightly causing leaks to develop among the passages between the faces of the end plate and the head. Since the large gasket covers each face and is clamped between the head and end plate by the peripherally spaced screws, the leaks among the passages are frequently not detected, As a result, a small quantity of beer is sometimes entrapped between the faces and the gasket creating almost ideal conditions for the growth of bacteria during periods when the equip- Patented Sept. 8, 1970 ment is idle and likely sources of contamination of the sterile beer being circulated through the tubes and passages at a later date.

SUMMARY OF THE INVENTION The present invention is directed to a heat exchanger of the character described above and particularly to an improved means for forming a seal between each tube within the housing and its correspondingly aligned passage Within the head. In accordance with a preferred embodiment of the invention, the face of the head is provided with an annular undercut recess surrounding the end of each passage, and an annular resilient gasket is located within each recess. Each gasket projects from the face of the head and is adapted to engage the face of the end plate of the housing when the head is drawn towards the end plate by the peripherally spaced screws. Since the total face area of the individual gaskets is much less than that of a full gasket, the force necessary to effect a seal between the end plate and the head is greatly reduced.

Each of the gaskets has suflicient thickness so that a space or gap is produced between the face of the head and the face of the end plate of the housing. Thus, if a leak did develop between one of the gask ts and one of the faces when the head bows, the escaping fluid would not flow into an adjacent passage but would drip to the floor below where it would be quickly detected. It has been found, however, that the separate and individual gaskets for the passages and aligned tubes will maintain an effective seal even when the head bows slightly when subjected to a wide temperature range.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of a heat exchanger incorporating sealing means constructed in accordance with the invention and with a center portion broken away;

FIG. 2 is an end view of the heat exchanger shown in FIG. 1 and showing the head in its closed position;

FIG. 3 is a fragmentary perspective view of the heat exchanger showing the head in an open position;

FIG. 4 is a fragmentary section taken through the head generally on the line 4-4 of FIG. 3;

FIG. 5 is an enlarged fragmentary section of a portion of the head shown in FIG. 4; and

FIG. 6 is an enlarged fragmentary section showing the head portion of FIG. 5 when the head is closed.

DESCRIPTION OF THE PREFERRED EMBODIMENT The heat exchanger shown in FIGS. 1 and 2 includes an elongated cylindrical casing or housing 10 supported on each end by a pedestal 12 and having a crowned end cover 14. The particular heat exchanger shown is intended for cooling beer and is adapted to receive a recirculated heat transfer fluid such as liquid ammonia through an inlet 15 connected to one end of the housing 10. Ammonia vapor is discharged from the opposite end of the housing 10 through an outlet 16 and is recirculated through a compresser system (not shown).

A circular header or end plate 18 is rigidly secured to the end of the housing 10 opposite the end cover 14 and includes a fiat face 20 having a plurality of cylindrical openings 22 (FIG. 6) each extending to a slightly larger counterbore 23. A corresponding plurality of tubes extend axially Within the housing 10, and each tube 25 has one end extending into one of the counterbores 23 where it is secured by a peripheral weld 26. The tubes 25 are supported in spaced relation within the housing by a pair of axially spaced vertical support members (not shown), and a plurality of U-shaped conduits 27 (FIG. 1) interconnect the end of adjacent tubes in the space enclosed by the end cover 14. Each opening 22 has a diameter the same as the inside diameter of the tube 25 received within its corresponding counterbore 23, and each weld 26 is ground so that it forms a smooth continuation of the inner surface of the corresponding tube 25 and opening 22.

A head 30 is mounted on the end plate 18 by a hinge 32. A flat circular face is formed on the head 30, and a plurality of peripherally spaced holes 36 are formed within the head. A set of screws 37 (FIG. 2) extend through the holes 36 and are threaded into correspondingly spaced holes 38 formed within the end plate 18.

A plurality of U-shaped return passages 40 (FIG. 4) are formed within the head 30 and the ends of each passage 40 terminate at the face 35. The head 30 also has a pair of straight passages 42 and 43 which are connected to an inlet line 44 (FIG. 1) and an outlet line 46, respectively. The passages 40, 42 and 43 are arranged within the head 30 so that they align with the openings 22, and each passage has an inner diameter the same as the inner diameter of its corresponding aligned opening 22. Thus the beer which is to be cooled is received within the inlet line 44 and is directed successively through the tubes 25 as a result of the interconnection provided by the U-shaped conduit 22 and the U-shaped return passages 40 until the beer is discharged from the line 46.

In accordance with the invention, an annular recess 48 (FIGS. 4-6) is formed within the face 35 of the head 30 surrounding each end of each of the passages 40, 42 and 43, and each recess 48 has a circumferential undercut formed by a frustoconical surface 49. An annular or ringlike resilient gasket 50 is positioned within each recess 48 and has a rectangular cross-section as shown in FIG. 5. Preferably, each gasket 50 is formed of neoprene and has a durometer within the range of 50 to 80. The thickness T of each gasket 50 is approximately twice the depth of its corresponding recess 48 so that each gasket 50 projects outwardly from the face 35 of the head 30. Thus when the head 35 is closed and the screws 38 are tightened, each gasket 50 is deformed so that its cross-sectional configuration resembles that shown in FIG. 6.

As a result of the thickness T of each gasket 50, when the head 30 is closed and secured to the end plate 18, a space or gap 52 (FIG. 6) is defined between the face 20 of the end plate 18 and the face 35 of the head 30. The compressive forces on each gasket 50 causes the gasket to expand into the undercut portion of its corresponding recess 48, and after the head has been closed for a period of time, each gasket 50 takes a partial set so that when the head is opened for cleaning, a portion of each gasket will remain within the undercut and thereby retain the gasket with the head 30.

From the drawings and the above description, it becomes apparent that a heat exchanger constructed in accordance with the invention provides desirable features and advantages. For example, by providing a separate resilient gasket 50 for each opening 22 within the end plate 18 and the correspondingly aligned passage within the head 30, and by constructing the gaskets with suflicient thickness to produce a gap 52 when the head 30 is closed against the end plate 18, a dependable and effective seal is formed between each opening 22 and corresponding passage. Furthermore, the gaskets 50 will maintain their seal even when the face 35 of the head 30 bows slightly when subjected to a substantial differential in temperature.

If a leak should develop between one of the gaskets 50 and the face 20 of the end plate 18, the escaping liquid would flow downwardly around the gaskets 50 located below the leaking gasket and would drip down onto the floor Where it would be easily detected. However, there is no danger of the escaping liquid flowing past another gasket 50 and into another opening 22 where it could possibly contaminate the fluid being cooled at a later time. The recesses 48 surrounding the ends of the passages 40, 42 and 43 also provide the feature of retaining each gasket 50 so that when the head 30 is moved to an open position for cleaning purposes, the gaskets 50 will remain in their proper positions concentrically aligned with the corresponding passages within the head 30.

The recesses 48 are preferably formed within the face 35 of the head 30 so that the tubes 25 may be easily cleaned without any danger of damaging the gaskets 50. However, it is conceivable that the recesses 48 could be formed within the face 20 of the end plate 18 in surrounding relation with the openings 22. Furthermore, while the gaskets 50 are preferably retained within the recesses 48, it is within the scope of the invention to eliminate the recesses 48 and to secure gaskets 50 to one of the faces 20 or 35 with a suitable cement.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A heat exchanger adapted for cooling a liquid food product, comprising a housing, header means connected to said housing and having a substantially fiat face, a plurality of generally parallel spaced tubes extending within said housing, each said tube having one end secured to said header means, means defining a corresponding opening within said face for each said tube, means connecting the opposite ends of selected said tubes, a head member releasably secured to said housing and including a substantially flat face disposed in closely spaced relation to said face of said header means, means defining a plurality of return passages within said head member, said passages having ends terminating at said face of said head member in substantially aligned relation with said openings for said tubes, said passages cooperating with said means connecting the opposite ends of said tubes to provide for directing a fluid through said tubes, a separate annular resilient gasket for each said tube within said housing and positioned in a compressed condition between said faces in surrounding relation with the correspondingly aligned said opening and passage, and means for retaining each said gasket on one of said faces to prevent leaking of the liquid from one said tube to another between said faces.

2. A heat exchanger as defined in claim 1 wherein said retaining means for each said gasket comprise an annular recess within one of said faces in surrounding relation with the adjacent end of the corresponding said passages and each said gasket including a portion projecting into the corresponding said recess.

3. A heat exchanger as defined in claim 2, wherein each said recess has a peripheral undercut, and said portion of the corresponding said gasket projects into said undercut when said head member is secured to said housing.

4. A heat exchanger as defined in claim 2 including hinge means pivotally connecting said head member to said housing, and said recesses being formed within said face of said head member.

5. A heat exchanger as defined in claim 1 wherein each said gasket has a durometer within the range of 50 to 80.

6. A heat exchanger as defined in claim 1 wherein each said tube and the corresponding said passage and said gasket each have substantially the same inside diameter.

7. A heat exchanger as defined in claim 1 wherein each said gasket has a rectangular cross-sectional configuration.

8. A heat exchanger as defined in claim 1 wherein the diameter of each said opening is substantially the same as 6 the inner diameters of the corresponding said tube and FOREIGN PATENTS k t. gas e References Cited 1 315,934 7/1929 Great Britain.

UNITED STATES PATENTS ROBERT A. OLEARY, Primary Examiner 360,924 4/1887 Solano 285-379 X 5 1,559,949 11/1925 Feldmeier 285-137 X A AVIS, ]R., Asslstant Examiner 2,926,937- 1/ 1960 Parsons 285350 2,628,850 2/1953 Summerville 285-137 X 3,357,482 12/1967 Irving et a]. 165-158 X 16577, 158, 178; 285-13, 127, 157, 379 

